You’re looking at a SubSonex jet with not one, but two PBS TJ100 turbojet engines. While an engine was added, the precious seat and canopy for the pilot were [sadly] removed.
It’s called the TRACER and isn’t for us to build—at least not right now—it exists as a proposed UAV remotely piloted aerial vehicle by Wisconsin-based Sonex and its partner of seven years, Navmar Applied Sciences Corporation (NASC). In the announcement, NASC and Sonex call the TRACER a “low-cost, high-performance UAV designed for speed, versatility, and survivability.” Changes from the single-engine SubSonex JSX-2, which has been on sale as a kit since 2014, include an extra 42 pounds of thrust from the engine, now in duplicate of course, and a resulting top speed estimated around 0.5 Mach or greater than 355 mph.
The engines are mounted from underneath on pylons that protrude from the aft fuselage, and a side view appears to show a small metal “thrust attenuator” like those of the original Cessna 525 CitationJet. The landing gear looks nearly identical to the single-engine SubSonex JSX-2, which has been on sale as a kit since 2014. The TRACER appears slightly more streamlined than the JSX-2, probably because of the absence of a canopy, and we can see extra antennae on the top of the fuselage and an elaborate camera set under the nose.